Method for the production of organosilicon compounds comprising carboxy radicals

ABSTRACT

Organosilicon compounds bearing carboxylic acid groups are easily and economically replaced in high yield by oxidation of a carbinol-functional organosilicon compound with an oxidizer in the presence of a moderator at a pH≧3. Carboxyl-functional organopolysiloxanes highly useful as textile softeners may be obtained by this method.

The invention relates to a method for the production of organosiliconcompounds comprising carboxy radicals.

Organosilicon compounds comprising carboxy groups are used widely astextile finishing agents. For the fabric treated in this way, goodsoft-hand effects coupled with a low yellowing tendency are achieved. Inaddition, organopolysiloxanes comprising carboxy groups are used in thefinishing of leather and as release agent.

Various methods are known for producing carboxy-functional silanes orsiloxanes. The insertion of the carboxylic acid groups via Grignardmethods

U.S. Pat. No. 2,763,675), from carboxyl compounds with activated CHgroup (reaction of haloalkylsiloxanes with cyanoacetic alkyl esters ormalonic esters and subsequent hydrolysis including decarboxylation; cf.U.S. Pat. No. 3,391,177), and the (co)hydrolysis of propionylchloride-functional silanes (obtainable by chlorinating hydrosilylationof α,β-unsaturated carboxylic esters with halosilanes; cf. U.S. Pat. No.3,143,524) are, however, less suited as industrial methods merely on thegrounds of cost. Furthermore, the proposed processes place highrequirements on the purity of the starting materials and the apparatusside of process control.

According to U.S. Pat. No. 2,900,363, U.S. Pat. No. 2,957,899 and U.S.Pat. No. 2,875,177, organosilicon compounds comprising carboxy groupscan be obtained by hydrosilylation of acrylonitrile and subsequent,acid- or base-catalyzed hydrolysis. Disadvantages of these methods arethe use of the toxicologically unacceptable acrylonitrile, the price ofother suitable, unsaturated, nitrile-functional starting materials, andthe hydrolysis being very slow on account of the heterogeneous reactionsystem, as a result of which a quantitative yield of free carboxylicacid groups can only be realized at very high cost.

Furthermore, organopolysiloxanes comprising carboxy groups are obtainedby reacting SiH-functional compounds with unsaturated carboxylic acidsin the presence of known hydrosilylation catalysts. The selectivity ofthe reaction, however, is very low since a significant secondaryreaction which takes place is the condensation of SiH with the acidicproton of the acid group, which proceeds with the elimination ofhydrogen, meaning that hydrolysis-labile, Si—O—C-linked structures areformed to a considerable degree.

It has therefore been proposed to replace the active hydrogen of theunsaturated carboxylic acid either with alkyl radicals (EP 569189 A) ora silyl radical (EP 196169 B1; U.S. Pat. No. 4,990,643) in order,following the addition reaction of said derivatives onto SiH-containingorganosilicon compounds, to hydrolytically release the carboxylic acidgroup again. However, the methods are likewise very expensive since thehydrolysis of the silyl protective group and in particular of the alkylesters requires, on account of the heterogeneous system, large amountsof water, long reaction times, high temperatures and—in the case of thealkyl esters—additionally strong acids and bases as catalyst, which inturn can lead to undesired secondary reactions on the siloxane backbone.Moreover, the water used in excess has to be removed again from theheterogeneous system when the reaction is complete, which is onlypossible through distillation with the help of an entrainer such astoluene since otherwise the mixture foams to a considerably high degree.

According to more recent patent specifications, silanes and siloxanescomprising carboxy groups can be obtained by adding a tertiary butylester with olefinic double bond, such as, for example, t-butylmethacrylate or t-butyl undecenoate, onto an SiH-containingorganosilicon compound in the presence of a hydrosilylation catalyst,and then converting the tertiary butyl ester group into thecorresponding carboxylic acid group with thermal or catalytic cleavageof gaseous isobutene (U.S. Pat. No. 5,504,233, U.S. Pat. No. 5,637,746).The greatest disadvantage of this method is that the cleavage reactionproceeds smoothly only at elevated temperature, and in the process largevolumes of a highly flammable, combustible gas with an extremely lowflash point are generated. In particular, the explosive gas mixturesformed with air represent a considerable danger potential. The processcan thus only be realized at high cost and requires special apparatusprecautions and know-how. In addition, during the catalytic cleavage ofthe tert-butyl ester, strong acids, such as p-toluenesulfonic acid,methanesulfonic acid or trifluoromethanesulfonic acid, are used in thepercentage range, which for their part, in their capacity as typicalequilibration catalysts, can adversely affect the reaction.

It is therefore the object to provide a cost-effective, simple andselective method for the production of organosilicon compoundscomprising carboxy radicals which makes the desired carboxy compoundsaccessible in a simple and rapid manner with high yields and whichsatisfies the ever increasing requirements in the art with regard tospace-time yield, and universal applicability. This object is achievedby the present invention.

The invention provides a method for the production of organosiliconcompounds (2) comprising carboxy radicals by oxidation of anorganosilicon compound (1) comprising carbinol radicals

with the help of a mediator (3) chosen from the group of aliphatic,cycloaliphatic, heterocyclic and aromatic NO—, NOH— and

containing compounds and an oxidizing agent (4),with the proviso that the reaction is carried out with constant controlof the pH at a pH of ≧3, and that the carbinol radicals in theorganosilicon compounds (1) used are oxidized predominantly to carboxyradicals.

By the method according to the invention, advantageously at least 75 mol%, preferably at least 80 mol %, particularly preferably at least 85 mol%, in particular at least 90 mol %, of the carbinol radicals present inthe organosilicon compounds (1) used are oxidized to carboxy radicals.

For the oxidation, all organosilicon compounds (1) are in principlesuitable if they have primary carbinol groups.

Preferably, the organosilicon compounds (1) comprising carbinol radicalsused in the method according to the invention are compounds comprisingunits of the formula

A′_(a)R_(b)X_(c)H_(d)SiO_((4-a-b-c-d)/2)  (I),

where A′ may be identical or different and is a radical of the formula

Y¹ is a di- or polyvalent, linear or cyclic, branched or unbranchedorganic radical which may be optionally substituted and/or interruptedby the atoms N, O, P, B, Si and S,

y corresponds to the valency of radical Y¹ and is ≧2, R may be identicalor different and is a monovalent, SiC-bonded optionally substitutedhydrocarbon radical, X may be identical or different and is chlorineatom, the group A′ or a radical of the formula —OR¹, where R¹ is ahydrogen atom or monovalent optionally substituted hydrocarbon radicalwhich may be interrupted by heteroatoms,

a is 0, 1 or 2, preferably 0 or 1,

b is 0, 1, 2 or 3,

c is 0, 1, 2 or 3, and

d is 0, 1, 2 or 3, preferably 0,

with the proviso that the sum a+b+c+d is ≦4 and the organosiliconcompound of the formula (I) has at least one radical A′ per molecule.

The organosilicon compounds (2) comprising carboxy radicals obtained bythe method according to the invention are compounds comprising units ofthe formula

A_(a)R_(b)X_(c)H_(d)SiO_((4-a-b-c-d)/2)  (III),

where A may be identical or different and is a radical of the formula

Y² is a hydrogen atom, an organic or inorganic cation, or a monovalentoptionally substituted hydrocarbon radical which may be interrupted byheteroatoms, and Y¹, R, X, a, b, c, d and y have the meanings given forthem above,with the proviso that the sum a+b+c+d is ≦4 and the organosiliconcompound of the formula (III) has at least one radical A per molecule.

The organosilicon compounds (1) used in the method according to theinvention may either be silanes, i.e. compounds of the formula (I) wherea+b+c+d=4, or polysiloxanes or organosilicone resin, i.e. compoundscomprising units of the formula (I), where a+b+c+d≦3, where, for thepurposes of the present invention, the term polysiloxane should beunderstood to include polymeric, oligomeric and also dimeric siloxanes.The compounds (1) used in the method according to the invention arepreferably organopolysiloxanes and organosilicone resin, particularlypreferably organopolysiloxanes, in particular those which consist ofunits of the formula (I).

Preferably used as organosilicon compounds (1) comprising carbinolradicals are those of the formula

A′_(v)R_(w)X_((3-v-w))Si  (I′)

A′_(v)R_(3-v)SiO(SiR₂O)_(n)(SiRA′O)_(o)SiR_(3-v)A′_(v)  (I″)

[A′_(v)R_(3-v)SiO_(1/2)]_(s)[SiO_(4/2)]  (I′″)

where A′, R and X have the meanings given for them above,

v is 0, 1, 2 or 3, preferably 0 or 1,

w is 0, 1, 2 or 3,

n is 0 or an integer from 1 to 2000,

o or an integer from 1 to 2000, preferably 0 to 500,

s can assume a value of from 0.2 to 6, preferably 0.4 to 4, inclusiveand describes the number of M units [A′_(v)R_(3-v)SiO_(1/2)] per Q unit[SiO_(4/2)] in the organosilicone resin,

with the proviso that they comprise at least one radical A′ permolecule.

Preferred organosilicon compounds (2) comprising carboxy radicals aretherefore those of the formula

A_(v)R_(w)X_((3-v-w))Si  (III′),

A_(v)R_(3-v)SiO(SiR₂O)_(n)(SIRAO)_(o)SiR_(3-v)A_(v)  (III″),

[A_(v)R_(3-v)Sio_(1/2)]_(s)[SiO_(4/2)]  (III′″),

where A, R, X, v, w, n, o and s have the meanings given for them above,with the proviso that they comprise at least one radical A per molecule.

Examples of radical R are alkyl radicals, such as the methyl, ethyl,n-propyl, isopropyl, 1-n-butyl, 2-n-butyl, isobutyl, tert-butyl,n-pentyl, isopentyl, neopentyl, tert-pentyl radicals; hexyl radicals,such as n-hexyl radical; heptyl radicals, such as the n-heptyl radical;octyl radicals, such as n-octyl radical and isooctyl radicals, such asthe 2,2,4-trimethylpentyl radical; nonyl radicals, such as the n-nonylradical; decyl radicals, such as the n-decyl radical; dodecyl radicals,such as the n-dodecyl radical; octadecyl radicals, such as n-octadecylradical; cycloalkyl radicals, such as the cyclopentyl, cyclohexyl,cycloheptyl radical and methylcyclohexyl radicals; alkenyl radicals,such as the vinyl, 1-propenyl and the 2-propenyl radical; aryl radicals,such as the phenyl, naphthyl, anthryl and phenanthryl radical; alkarylradicals, such as o-, m-, p-tolyl radicals; xylyl radicals andethylphenyl radicals; and aralkyl radicals, such as the benzyl radical,the α- and the β-phenylethyl radical.

Examples of substituted radicals R are haloalkyl radicals, such as3,3,3-trifluoro-n-propyl radical, the 2,2,2,2′,2′,2′-hexafluoroisopropylradical, the heptafluoroisopropyl radical and haloaryl radicals, such asthe o-, m- and p-chlorophenyl radical, acylated aminoalkyl radicals,such as the N-acetylaminopropyl, N-acetylcyclohexylaminopropyl,N-acetyldimethylamino-propyl, N-acetyldiethylaminopropyl radical and theN,N′-diacetylaminoethylaminopropyl radical, quat-functional radicals,such as, for example, —(CH₂)₃—N(CH₃)₃ ⁺ and—(CH₂)₃—NH—CH₂—CH(OH)—CH₂—N(CH₃)₃ ⁺, including the anions required tocompensate for the cationic charge, hydroxyl-functional radicals, suchas those from sec. or tert. aliphatic or aromatic alcohols, such as, forexample, the phenol or eugenol radical, carboxylic-acid-functionalradicals, and derivatives or salts thereof, such as the acetic acid,3-carboxypropyl, 4-carboxybutyl, 10-carboxydecyl,3-(2,5-dioxotetrahydrofuranyl)propyl, 3-(ethane-1,2-dicarboxylicacid)propyl, 3-acryloxypropyl, 3-methacryloxypropyl or undecenesilylester radical, epoxy-functional radicals, such as, for example, thosefrom the group consisting of

ketone-functional radicals, alkyl- or acyl-terminated, SiC- orSiOC-bonded polyalkylene oxide radicals, such as, for example, thosewhich are derived from polyethylene glycol, polypropylene glycol,poly(1,4-butanediol) and mixed polymers thereof, phosphonato-functionalradicals, such as, for example, phosphonato-alkyl radicals,silalactone-functional radicals, and glycoside-functional radicals, suchas, for example, those in which the glycoside radical, which can beconstructed from 1 to 10 monosaccharide units, is bonded via an alkyleneor oxyalkylene spacer, and in which at least some primary hydroxy groupsare provided with acyl or alkyl protective groups.

The radical R is preferably a hydrocarbon radical having 1 to 18 carbonatom(s) optionally substituted by halogen groups, tert-hydroxy groups,acylated amino groups, groups comprising quaternary nitrogen, carboxylicacid or carboxylic acid derivative groups or epoxy groups, or is analkyl- or acyl-terminated SiC- or SiOC-bonded polyalkylene oxideradical, particularly preferably the methyl, ethyl, vinyl, n-propyl,n-octyl, n-dodecyl, n-octadecyl and phenyl radical, in particular themethyl and phenyl radical.

If the organosilicon compounds according to the invention areorganopolysiloxanes, at least 50%, particularly preferably at least 90%,of all radicals R have the meaning methyl or phenyl radical.

Examples of radicals R¹ are the examples given for radical R.Preferably, the radical R¹ is hydrogen atom or an alkyl radical having 1to 8 carbon atom(s), which may be optionally interrupted by ether oxygenatoms. Particular preference is given to hydrogen atom, the methyl,ethyl, propyl and butyl radical.

Examples of radical X are chlorine atom, the OH group, the group A′, andalkoxy radicals, such as the methoxy, ethoxy, n-propoxy, isopropoxy,1-butoxy, 2-butoxy, 1-pentyloxy, 1-hexyloxy, 1-octyloxy, 2-octyloxy,isooctyloxy, 1-decyloxy, 1-dodecyloxy, myristyloxy, cetyloxy orstearoyloxy radical. Radical X is preferably chlorine atom, the radicalA′, the OH group, the methoxy, ethoxy, propoxy, butoxy, myristyloxy,cetyloxy or stearoyloxy radical, particularly preferably chlorine atom,the OH group, the methoxy, ethoxy, propoxy and butoxy radical.

Examples of radical Y¹ are alkylene radicals, such as the methylene,ethylene, propylene, 2-methylpropylene, butylene, pentylene, hexylene,heptylene, octylene, nonylene, undecylene and heptadecylene radical,cyclic and polycyclic alkylene radicals, such as, for example, thecyclohexylene, methylcyclohexylene, dimethylcyclohexylene andnorbornylene radical, unsaturated alkylene radicals, such as theethenylene, 1-propenylene, 1-butenylene and 2-butenylene radical, ether-and polyether-functional alkylene radicals, and alkylene radicals whichare interrupted by a carboxylic acid derivative group, such as, forexample, carboxylic ester or carboxamide group, or carbonic acidderivative group, such as, for example, carbonic ester, urethane or ureagroup.

Radical Y¹ is preferably a di- to decavalent, preferably di- topentavalent, hydrocarbon radical which can be optionally substituted byone or more units —C(O)—, —C(O)O—, —C(O)NR¹—, —O—C(O)O—, —O—C(O)NR¹—,—NR¹—C(O)—NR¹—, —O—, —S— and substituted by tert-hydroxy, alkoxy,mercaptoalkyl, carbonyl, carboxyl, nitrile or oxiranyl groups.

Preferably, radical Y¹ is

A) the ethylene, propylene, 2-methylpropylene, butylene, pentylene,nonylene and undecylene radical, the radicals

B) a radical of the formula

—R²-(Z-CH₂CH₂)_(z)-Z′-R²—  (V),

where the radicals R² may be identical or different and are a divalenthydrocarbon radical having 1 to 10 (preferably 1 to 6) carbon atoms, Zis the unit —O— or —N[—C(O)—(CH₂)_(h)—H]—, where h≧1 (preferably 1-6,particularly preferably 1-3), and Z′ is the groups —O—C(O)—, —NH—C(O)—,—O—C(O)O—, —NH—C(O)O— or —NH—C(O)NH—, preferably —O—C(O)— or —NH—C(O)—,and z is an integer from 0 to 4 (preferably 0 or 1), or

C) a radical of the formula

—R³—{[CH₂CH₂O]_(e)[C₃H₆O]_(f)—[(CH₂)₄O]_(g)—B—}_(x−1)  (VI),

where R³ is a divalent, trivalent or tetravalent organic radical having2 to 10 carbon atoms which may be substituted by one or more units

B is a methylene, ethylene or n-propylene spacer, e, f, g, independentlyof one another, are each 0 or an integer from 1-200, preferably 0-100,particularly preferably 0-50, with the proviso that the sum e+f+g is ≧1,and x corresponds to the valency of radical R³ and can assume the value2, 3 or 4.

Radical Y¹ is particularly preferably the ethylene, propylene,2-methylpropylene, butylene, pentylene, nonylene and undecylene radical,the radicals

with B, e, f and g in the meanings given for them above.

Preferably y corresponds to the valency of Y¹ and is an integer from 2to 10, preferably 2 to 5.

Preferably, radical Y² is hydrogen atom, an organic or inorganic cationor a monovalent hydrocarbon radical having 1 to 18 carbon atom(s),particularly preferably hydrogen atom, tetraalkylammonium,trialkylammonium, dialkylammonium, alkylammonium, ammonium, lithium,sodium, potassium and cesium.

The mediator (3) used is preferably at least one compound chosen fromthe group of aliphatic, cycloaliphatic, heterocyclic or aromaticcompounds which comprises at least one N-hydroxy, oxime, nitroso, N-oxylor N-oxy function. Examples of such compounds are described in detail inU.S. Pat. No. 6,169,213 B1 (incorporated by reference), in particularcolumn 5, line 63 to column 25, line 58, and US 2003073871 A1(incorporated by reference), in particular page 2, paragraph [0023] topage 3, paragraph [0030] inclusive.

Preferred mediators (3) are nitroxyl radicals of the general formulae(XI) and (XII)

where

R¹⁶ is identical or different and is phenyl, aryl-C₁-C₅-alkyl,C₁-C₁₂-alkyl, C₁-C₅-alkoxy, C₁-C₁₀-carbonyl and carbonyl-C₁-C₆-alkylradical, where

the phenyl radicals may be unsubstituted or mono- or polysubstituted bya radical R¹⁸, and the aryl-C₁-C₅-alkyl, C₁-C₁₂-alkyl, C₁-C₅-alkoxy,C₁-C₁₀-carbonyl and carbonyl-C₁-C₆-alkyl radicals may be saturated orunsaturated, branched or unbranched and may be mono- or polysubstitutedby a radical R¹⁸, where

R¹⁸ may be present one or more times and is identical or different andis hydroxy, formyl, carboxy radical, ester or salt of the carboxyradical, carbamoyl, sulfono, sulfamoyl, nitro, nitroso, amino, phenyl,benzoyl, C₁-C₅-alkyl, C₁-C₅-alkoxy radical, C₁-C₅-alkylcarbonyl,

R¹⁷ is identical or different and is a hydrogen atom or hydroxy,mercapto, formyl, cyano, carbamoyl, carboxy radical, ester or salt ofthe carboxy radical, sulfono radical, ester or salt of the sulfonoradical, sulfamoyl, nitro, nitroso, amino, phenyl, aryl-C₁-C₅-alkyl,C₁-C₁₂-alkyl, C₁-C₅-alkoxy, C₁-C₁₀-carbonyl and carbonyl-C₁-C₆-alkylradical, phospho, phosphono, phosphonooxy radical, ester or salt of thephosphonooxy radical, where

the carbamoyl, sulfamoyl, amino, mercapto and phenyl radicals may beunsubstituted or mono- or polysubstituted by a radical R¹²,

and the aryl-C₁-C₅-alkyl, C₁-C₁₂-alkyl, C₁-C₅-alkoxy, C₁-C₁₀-carbonyland carbonyl-C₁-C₆-alkyl radicals may be saturated or unsaturated,branched or unbranched and may be mono- or polysubstituted by a radicalR¹², and a [—CR¹⁷R¹⁷—] group may be replaced by oxygen, an optionallyC₁-C₅-alkyl-substituted imino radical, a (hydroxy)imino radical, acarbonyl function or a vinylidene function optionally mono- ordisubstituted by R¹²,

and two adjacent groups [—CR¹⁷R¹⁷—] may be replaced by a group[—CR¹⁷═CR¹⁷—], [—CR¹⁷═N—] or [—CR¹⁷═N(O)—].

Mediators (3) preferably used according to the method of the inventionare:

-   2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO),-   4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl,-   4-acetamido-2,2,6,6-tetramethylpiperidin-1-oxyl,-   4-acetoxy-2,2,6,6-tetramethylpiperidin-1-oxyl,-   4-benzoyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl,-   PIPO (polymer immobilized piperidinyloxyl),-   3-amino-N-hydroxyphthalimide,-   4-amino-N-hydroxyphthalimide,-   N-hydroxyphthalimide,-   3-hydroxy-N-hydroxyphthalimide,-   3-methoxy-N-hydroxyphthalimide,-   3,4-dimethoxy-N-hydroxyphthalimide,-   4,5-dimethoxy-N-hydroxyphthalimide,-   3,6-dihydroxy-N-hydroxyphthalimide,-   3,6-dimethoxy-N-hydroxyphthalimide,-   3-methyl-N-hydroxyphthalimide,-   4-methyl-N-hydroxyphthalimide,-   3,4-dimethyl-N-hydroxyphthalimide,-   3,5-dimethyl-N-hydroxyphthalimide,-   3,6-dimethyl-N-hydroxyphthalimide,-   3-isopropyl-6-methyl-N-hydroxyphthalimide,-   3-nitro-N-hydroxyphthalimide,-   4-nitro-N-hydroxyphthalimide,-   1-hydroxy-1H-benzotriazole,-   violuric acid,-   N-hydroxyacetanilide,-   3-nitrosoquinoline-2,4-diol,-   2,4-dihydroxy-3-nitrosopyridine,-   2,6-dihydroxy-3-nitrosopyridine,-   2,4-dinitroso-1,3-dihydroxybenzene,-   2-nitroso-1-naphthol-4-sulfonic acid and-   1-nitroso-2-naphthol-3,6-disulfonic acid,    where-   2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO),-   4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl,-   4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl,-   4-acetoxy-2,2,6,6-tetramethylpiperidin-1-oxyl,-   4-benzoyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl and-   PIPO (polymer immobilized piperidinyloxyl)    are particularly preferred.

In one particular embodiment, the nitroxyl radicals of the generalformulae (XI) and (XII) can also be linked to a polymeric structure viaone or more radicals R¹⁷. The literature describes a large number ofsuch polymer-bound nitroxyl radicals (cf. e.g. the literature cited inEP 1 302 456 A1, page 4, lines 39 to 43). Examples are PIPO (polymerimmobilized piperidinyloxyl), SiO₂-supported TEMPO, polystyrene- andpolyacrylic-acid-supported TEMPO.

According to the method of the invention, the mediator (3) is usedpreferably in amounts of from 0.01 to 100 mol %, preferably 0.1 to 20mol %, particularly preferably 0.1 to 5 mol %, based on the molar amountof carbinol groups present in the organosilicon compounds used.

The method according to the invention can be carried out with one ormore of the described mediators (3), preferably with one or twomediators (3), particularly preferably with one mediator (3). Themediator (3) can be dissolved in an organic or aqueous phase or be usedin supported form as an independent phase.

According to the method of the invention, the corresponding, activeoxoammonium species is produced from the mediator (3) in situ by theoxidizing agent and is not isolated. In one particular embodiment,however, the mediator (3) can be converted into the active oxoammoniumspecies in a separate upstream oxidation reaction, isolated and thenused separately.

In the method according to the invention, the oxidizing agents (4) usedare preferably air, oxygen, hydrogen peroxide, organic peroxides,perborates or persulfates, organic or inorganic peracids, salts andderivatives of the peracids, chlorine, bromine, iodine, hypohalic acidsand salts thereof, e.g. in the form of bleaching liquor, halic acids andsalts thereof, halogen acids and salts thereof, Fe(CN)₆ ³⁻, N-chlorocompounds. Oxidizing agents may, for example, however, also be metaloxides or anodes of electrolysis cells. Furthermore, the oxidizing agentused can also be generated in situ, e.g. electrochemically, byhydrolysis, such as, for example, by hydrolysis of N-chloro compounds,or by redox reactions, such as, for example, in the case of hypochloriteor hypobromite solutions by disproportionation of chlorine or bromine,respectively, in alkaline solution, or as, for example, in the case ofthe redox reaction between hypochlorite and bromide, which leads to theformation of hypobromite.

In the case of salt-like oxidizing agents, sodium, potassium, calcium,ammonium or tetraalkylammonium are preferred as counterions.

The oxidizing agents (4) can be used individually or in a mixture, ifappropriate in each case in combination with enzymes, where, for thepurposes of the invention, the term enzyme also includes enzymaticallyactive proteins or peptides or prosthetic groups of enzymes.

Examples of enzymes which can be used for the purposes of the methodaccording to the invention are described in detail in U.S. Pat. No.6,169,213 B1 (column 26, line 29 to column 28, line 6), whereoxidoreductases of classes 1.1.1 to 1.97 according to the InternationalEnzyme Nomenclature, Committee of the International Union ofBiochemistry and Molecular Biology (Enzyme Nomenclature Academic Press,Inc., 1992, p. 24-154) are preferably used.

If enzymes are used, preference is given to using oxidoreductases of theclasses specified below:

enzymes of class 1.1.5 (quinones as acceptor),

enzymes of class 1.1.3 (oxygen as acceptor),

enzymes of class 1.2.3 (oxygen as acceptor),

enzymes of class 1.3.3 (oxygen as acceptor),

enzymes of class 1.3.5 (quinones as acceptor),

enzymes of class 1.4.3 (oxygen as acceptor),

enzymes of class 1.5.3 (oxygen as acceptor),

enzymes of class 1.5.5 (quinones as acceptor),

enzymes of class 1.6.5 (quinones as acceptor),

enzymes of class 1.7.3 (oxygen as acceptor),

enzymes of class 1.8.3 (oxygen as acceptor),

enzymes of class 1.8.5 (quinones as acceptor),

enzymes of class 1.9.3 (oxygen as acceptor),

enzymes of class 1.10.3 (oxygen as acceptor),

peroxidases of class 1.11.1,

and enzymes of classes 1.12, 1.13, 1.14, 1.15 and 1.16, where

cellobiose: quinone-1-oxidoreductase (1.1.5.1),

bilirubin oxidase (1.3.3.5),

catechol oxidase (tyrosinase) (1.10.3.1),

L-ascorbate oxidase (1.10.3.3),

o-aminophenol oxidase (1.10.3.4)

laccase (benzenediol: oxigen oxidoreductase) (1.10.3.2)

cytochrome-C-peroxidases (1.11.1.5),

catalase (1.11.1.6),

peroxidase (1.11.1.7),

iodide peroxidase (1.11.1.8),

glutathione peroxidase (1.11.1.9),

chloride peroxidase (1.11.1.10),

L-ascorbate peroxidase (1.11.1.11),

phospholipid hydroperoxide glutathione peroxidase (1.11.1.12),

manganese peroxidase (1.11.1.13),

diarylpropane peroxidase (ligninase, lignin peroxidase) (1.11.1.14),

superoxide dismutase (1.15.1.1) and

ferroxidase (1.16.3.1)

are particularly preferred.

The specified enzymes are commercially available or can be obtained bystandard methods. Suitable organisms for producing the enzymes are, forexample, plants, animal cells, bacteria and fungi. In principle,naturally occurring and also genetically modified organisms may beenzyme producers. Parts of single-cell or multicell organisms arelikewise conceivable as enzyme producers, primarily cell cultures. Forthe particularly preferred enzymes, such as those from the group 1.11.1,but primarily 1.10.3, and in particular for the production of laccases,for example white rot fungi, such as Pleurotus, Phlebia and Trametes,are used.

The oxidizing agents (4) used are preferably used in concentrations of0.1 M up to their respective saturation concentration.

If the oxidizing agent (4) used in the method according to the inventionis a 2-electron oxidizing agent, then this is preferably used in anamount of from 0.2 to 250 mol %, preferably 100 to 220 mol %,particularly preferably 150 to 210 mol %, in each case based on themolar amount of the carbinol groups present in the organosiliconcompounds used. If, by contrast, the oxidizing agent used in the methodaccording to the invention is a 1-electron oxidizing agent, then this ispreferably used in an amount of from 0.4 up to 500 mol %, preferably 200to 440 mol %, particularly preferably 300 to 420 mol %, in each casebased on the molar amount of the carbinol groups present in theorganosilicon compounds used.

If, in the method according to the invention, metal oxides are used asoxidizing agents (4), bismuth(III) oxide, iridium(III) oxide, cerium(IV)oxide, cobalt(II) oxide, cobalt(III) oxide, iron(III) oxide,manganese(IV) oxide, tin(IV) oxide, niobium(V) oxide, antimony(V) oxide,indium(III) oxide, mercury(II) oxide, lead(IV) oxide, silver(I) oxide,Cu(II) oxide, palladium(II) oxide, in particular lead(IV) oxide,manganese(IV) oxide, silver(I) oxide, Cu(II) oxide and palladium(II)oxide are preferred.

If, in the method according to the invention, the oxidation takes placewith the help of electrodes of an electrolysis cell, then the electrodesused may be identical or different and preferably consist of carbon,iron, lead, lead dioxide, copper, nickel, zinc, cadmium, mercury,tantalum, titanium, silver, platinum, platinized platinum, palladium,rhodium, gold or of alloys of said compounds. Particular preference isgiven to electrodes made of stainless steel, tantalum, titanium,rhodium, platinum or gold, in particular electrodes made of stainlesssteel, with stainless steels of group 1.4xxx (according to DIN 17850)being very particularly preferred.

The electrodes may optionally have been coated with other substances bydeposition, sputtering, galvanization or similar methods. The surfacearea of the electrodes may have been increased by suitable methods, forexample by grinding, polishing, sandblasting, etching or erosion.

In addition, in the method according to the invention, all furthersubstances (5) which have also hitherto been used in mediated oxidationscan be used. Possible additives are halogens, e.g. bromine, or salts,e.g. alkali metal, alkaline earth metal or ammonium halides or sulfates,carbonates, hydrogen carbonates, phosphoric acid and alkali metal,alkaline earth metal or ammonium salts thereof or carbon dioxide. Theseadditives can be added to the oxidizing agent or to the phase comprisingthe oxidizing agent or to the organosilicon compound (1) to be oxidizedor to the phase comprising the organosilicon compound (1) to beoxidized, optionally in dissolved form, or can be fed to the reactionmixture optionally in dissolved form as further component.

If, in the method according to the invention, hypochlorite, for example,is used as oxidizing agent (4), the addition of bromine or bromide,which is preferably used in amounts of from 0.01 to 100 mol %, based onthe amount of hypochlorite used, preferably in amounts of between 1 and50 mol %, for example, is preferred.

In addition, in the method according to the invention, substances (6)are added to the reaction mixture with whose help the pH of the reactionmixture can be changed or kept constant. Examples of such substances (6)are buffers, such as, for example, sodium hydrogen carbonate, disodiumhydrogen phosphate or sodium dihydrogen phosphate, or buffer mixtures,acids, such as, for example, carbon dioxide, phosphoric acid,hydrochloric acid or sulfuric acid, and bases, such as, for example,alkali(ne earth) metal hydroxides, carbonates or phosphates, such asNaOH, KOH, Na₂CO₃ or Na₃PO₄.

The method according to the invention can be carried out with or withoutadditional solvents (7) as 1-phase or multiphase reaction or indispersion, such as, for example, microemulsion or macroemulsion.

If, in the method according to the invention, solvent (7) is used, it ispreferably inert solvents which do not influence the redox process.Examples of suitable solvents (7), which can be used in the methodaccording to the invention individually or in a mixture with oneanother, are pentane, petroleum ether, n-hexane, hexane isomer mixtures,cyclohexane, heptane, octane, solvent naphtha, decalin, benzene,toluene, xylene, diethyl ether, di-n-propyl ether, diisopropyl ether,di-n-butyl ether, methyl tert-butyl ether, ethylene glycol dimethylether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether,tetrahydrofuran, dioxane, methyl acetate, ethyl acetate, n-, sec- andtert-butyl acetate, dichloromethane, trichloromethane,tetrachloromethane, 1,2-dichloroethane, trichloroethylene,tetrachloroethylene, chlorobenzene, 1-chloronaphthalene, ethylenecarbonate, propylene carbonate, CO₂, acetonitrile, acetamide,tetrahydro-1,3-dimethyl-2(1H)-pyrimidinone (DMPU),hexamethylphosphortriamide (HMPT), dimethyl sulfoxide (DMSO), sulfolane,acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK),diisopropyl ketone, ionic liquids, linear and cyclic siloxanes, andmixtures of said solvents.

If, in the method according to the invention, additional solvents (7)are used, the amounts are preferably from 0.1 to 200 parts by weight,particularly preferably 1 to 100 parts by weight, in each case based on100 parts by weight of the weight of the organosilicon compound (1) tobe oxidized.

If the method according to the invention is carried out as 2-phasereaction, then as good as possible a homogenization of the immisciblephases and the provision of a large internal reaction area is to beensured, such as, for example, through generating an average particlesize of <500 μm. The intense thorough mixing of the reaction phases cantake place in principle with all mixing systems known according to theprior art, such as, for example, stirrers of all types, high-speedstirrers, such as, for example, those available under the trade markUltra-Turrax® or similar dissolver system, by means of ultrasound probesor baths, electric, magnetic or electromagnetic fields etc., or—such as,for example, when carrying out the reaction continuously—with static ormoving mixing elements or nozzles, and through turbulent flow, orthrough any combinations thereof.

If the method according to the invention is carried out in dispersion,then emulsifiers or surface-active agents (8), such as, for example,nonionic, anionic, cationic or amphoteric emulsifiers, may accordinglybe present, where the dispersion can be produced in any manner known tothe person skilled in the art. However, the emulsifier or surface-activeagent which may be used may also be the organosilicon compound (1) to beoxidized itself or the reaction product (2) obtained by the methodaccording to the invention.

The components used in the method according to the invention may in eachcase be one type of such a component, or a mixture of at least two typesof a particular component.

In the method according to the invention, the components used can bearbitrarily mixed together, fed to the reaction and/or reacted in amanner known per se. The method according to the invention can becarried out batchwise, semicontinuously or entirely continuously inreactor systems suitable for this purpose, such as, for example, batchreactor, batch reactor cascade, loop reactor, stream tube, tubularreactor, microreactor, centrifugal pumps and any combinations thereof.

In the case of a strongly exothermic reaction and/or batchwiseprocedure, a metered addition of components (4), optionally in a mixturewith component (6), to a mixture consisting of components (1), (3) and(6) and optionally (5), (7) and/or (8) is preferred. In the case of acontinuous procedure, a cometering of three volume streams, consistingof volume stream A containing components (1) and (3) and optionally (7)and/or (8), volume stream B containing components (5) and (6) and volumestream C containing component (4) optionally in a mixture with component(6) preferably takes place.

The method according to the invention is preferably carried out withconstant monitoring of the pH at a pH of pH≧3 and pH≦12, preferablypH≧4, particularly preferably pH≧6. The pH is adjusted here preferablyduring the reaction through the simultaneous addition of component (6).If desired, component (6) can also be added in a sufficient amountbefore the reaction and the pH of the reaction mixture can therefore bekept constant for the duration of the reaction.

In addition, the method according to the invention is carried out at atemperature of preferably −100 to +150° C., preferably −50 to +100° C.,particularly preferably −20 to +75° C.

The reaction times are preferably 0.1 seconds to 72 hours, preferably 1second to 48 hours, particularly preferably 1 second to 24 hours.

When the reaction according to the invention is complete, the reactionproducts can be separated off from any reaction auxiliaries used andisolated by any hitherto known process steps. Preferably, the productsare isolated in the form of their free acids by acidifying the reactionmixture to pH values ≦3. The acids used here are preferably those whosepK_(a) value is less than the pK_(a) value of the carboxy group of theorganosilicon compounds (2) comprising carboxy radicals according to theinvention. Examples of such acids are trifluoroacetic acid, HCl, H₂SO₂,methanesulfonic acids, trifluoromethanesulfonic acids andp-toluenesulfonic acids. As a result, the formed free siloxanecarboxylicacids soluble in organic medium are also separated off from saltspresent, e.g. inorganic salts. If desired, after the reaction, readilyvolatile components and any solvent used can also be removed bydistillation.

Furthermore, the method according to the invention can be followed byany further process steps, by means of which the desired properties ofthe organosilicon compound (2) obtained by the method according to theinvention can be adjusted in a targeted manner. The procedure of theprocess steps is governed here primarily by the current prior art andtakes place in the manner known to the person skilled in the art.

Examples of such consecutive reactions are, in particular, equilibrationreactions with, for example, organopolysiloxanes, condensation of theorganosilicon compound (2) with other organosilicon compounds capable ofcondensation reactions, such as, for example, silanols,alkoxy-functional silanes and silanol- or alkoxy-functionalpolysiloxanes or organosilicone resins, and also the organofunctionalmodification of the organosilicon compound, such as, for example,esterification, amide formation or anhydride formation.

The method according to the invention offers a number of advantages overthe prior art. It is preparatively simple to realize without specialexpenditure on apparatus and, due to the low reaction temperature andthe catalytic use of the mediators employed, cost-effective,resource-conserving and thus sustainably environmentally compatible.

The method according to the invention can be used universally andflexibly. It is equally suitable for a discontinuous and in particular acontinuous procedure, which means a further advantage with regard tocosts, flexibility and space-time yield.

Through the selective, rapid and virtually quantitative oxidation of thecarbinol groups, excellent reaction yields are obtained in shortreaction times even in the case of polymeric organosilicon compounds.The reaction products can be isolated cleanly and in a simple manner. Inaddition, scarcely any by-products are formed in the reaction accordingto the invention. Furthermore, the relatively mild reaction conditionspermit the use of the method according to the invention also onorganosilicon compounds (1) with sensitive functional groups.

The carboxy-radical-comprising organosilicon compounds (2) obtained bythe method according to the invention are exceptionally suitable, forexample, on account of the reactivity of the carboxy group toward O, Nand S nucleophiles, for the permanent finishing of correspondingmaterials, such as, for example, of natural fibers (wool, silk, cotton,keratin fibers, etc.), cellulose and cellulose fibers, and blendsthereof with synthetic fibers such as polypropylene, polyester orpolyamide fibers. Typical target effects are a soft, flowing feel, lowtendency toward yellowing, improved elasticity, antistatic properties,low coefficients of friction, surface smoothness, shine, creaserecovery, colorfastnesses, washing resistance, hydrophilicity,tear-propagation resistance, reduced pilling tendency, “easy-care” and“soil-release” properties, improved wear comfort, high resistance of thefinishing to washing and care processes, improved industrialprocessability, e.g. with regard to rate of processing and production.

In addition, the organosilicon compounds (2) comprising carboxy radicalsare suitable as auxiliary in the tanning and dressing of leather, andalso for the sizing and surface refining of paper. Organosiliconcompounds comprising carboxy radicals can also be used as additives incoatings and paints, where they lead, for example, to a reduction in thesurface roughness and thus to a reduction in the slip resistance of thepaint.

Other use possibilities are the use as additive in cosmeticformulations, for example in skincare compositions, as conditioner inhair-washing compositions or as humectant generally.

In addition, silicones comprising carboxy radicals are used inprotective compositions for buildings, and—as surface-activesubstances—for producing aqueous emulsions.

Moreover, organosilicon compounds comprising carboxy radicals can alsobe used as a chemical building block such as, for example, for producingplastics or resins, and as intermediate for further syntheses.

The process examples below explain the invention. Unless statedotherwise, all indications of parts with percentages are based on theweight. Furthermore, all viscosity data refer to a temperature of 25° C.Unless stated otherwise, the examples below are carried out at thepressure of the ambient atmosphere, i.e. at about 1000 hPa, and at roomtemperature, i.e. at about 20° C., or at a temperature which isestablished upon combining the reactants at room temperature withoutadditional heating or cooling.

EXAMPLE 13-[2-(2-Carboxyethyl)-1,1,2,2-tetramethyl-disiloxanyl]propionic acid

20 g (80 mmol) of3-[2-(3-hydroxypropyl)-1,1,2,2-tetra-methyldisiloxanyl]propanol aredissolved together with 758 mg (4.4 mmol) of 4-hydroxy-TEMPO in 40 ml ofethyl acetate. 166 ml of technical bleaching liquor are adjusted to a pHof 9.5 with 20 percent sulfuric acid. Synchronously, these solutions areadded dropwise to a reaction vessel cooled to 0° C. with vigorousstirring. The pH of the reaction mixture is maintained at about 8through the simultaneous addition of 2N NaOH.

The phases are separated, and the aqueous phase is washed with 10 ml ofethyl acetate and acidified with conc. HCl to pH 1. Extraction with MTBEand concentration by evaporation gives 19 g of solid, which is pure3-[2-(2-carboxyethyl)-1,1,2,2-tetramethyl-disiloxanyl]propionic acid.

EXAMPLE 2 α,ω-(2-Carboxyethyl)-modified polydimethyl-siloxane

The reaction takes place analogously to Example 1 using a polysiloxaneconsisting of dimethylsiloxy and (3-hydroxypropyl)dimethylsiloxy unitswith a carbinol group content of 3.19% by weight and a viscosity ofabout 50 mPa·s (at 25° C.). When the reaction is complete, the neutralreaction mixture is acidified with 10% strength HCl, the ethyl acetatephase is separated off and the mixture is concentrated by evaporation.This gives the α,ω-(2-carboxyethyl)-modified polydimethylsiloxane as avirtually colorless, clear oil with a carboxy group content of 8.23% byweight.

EXAMPLE 3 α,ω-(2-Carboxyethyl)-modified polydimethyl-siloxane

The reaction takes place analogously to Example 1 using a polysiloxaneconsisting of dimethylsiloxy and (3-hydroxypropyl)dimethylsiloxy unitswith a carbinol group content of 0.81% by weight and a viscosity ofabout 110 mPa·s (at 25° C.). When the reaction is complete, the neutralreaction mixture is acidified with 10% strength HCl, the ethyl acetatephase is separated off and the mixture is concentrated by evaporation.This gives the α,ω-(2-carboxyethyl)-modified polydimethylsiloxane as avirtually colorless, clear oil with a carboxy group content of 2.14% byweight.

EXAMPLE 4 laterally 2-carboxyethyl-modified poly-dimethylsiloxane

The reaction takes place analogously to Example 1 using a polysiloxaneconsisting of trimethylsiloxy, dimethylsiloxy and(3-hydroxypropyl)methylsiloxy units with a carbinol group content of4.4% by weight and a viscosity of about 350 mPa·s (at 25° C.). When thereaction is complete, the neutral reaction mixture is acidified with 10%strength HCl, the ethyl acetate phase is separated off and the mixtureis concentrated by evaporation. This gives theα,ω-(2-carboxyethyl)-modified polydimethylsiloxane as a slightlyyellowish, clear oil with a carboxy group content of 11.6% by weight.

EXAMPLE 5 laterally 2-carboxyethyl-modified poly-dimethylsiloxane

The reaction takes place analogously to Example 1 using a polysiloxaneconsisting of trimethylsiloxy, dimethylsiloxy and3-(hydroxypropyl)methylsiloxy units with a carbinol group content of1.08% by weight and a viscosity of about 550 mPa·s (at 25° C.). When thereaction is complete, the neutral reaction mixture is acidified with 10%strength HCl, the ethyl acetate phase is separated off, and the mixtureis concentrated by evaporation. This gives theα,ω-(2-carboxyethyl)-modified polydimethylsiloxane as a pale yellow,clear oil with a carboxy group content of 2.85% by weight.

EXAMPLE 6 laterally 2-carboxyethyl-modified poly-dimethylsiloxane

The reaction takes place analogously to Example 1 using a polysiloxaneconsisting of trimethylsiloxy, dimethylsiloxy and(3-hydroxypropyl)methylsiloxy units with a carbinol group content of0.76% by weight and a viscosity of about 260 mPa·s (at 25° C.). When thereaction is complete, the neutral reaction mixture is acidified with 10%strength HCl, the ethyl acetate phase is separated off, and the mixtureis concentrated by evaporation. This gives theα,ω-(2-carboxyethyl)-modified polydimethylsiloxane as a virtuallycolorless, clear oil with a carboxy group content of 2.02% by weight.

EXAMPLE 7 laterally 2-carboxyethyl-modified poly-dimethylsiloxane

The reaction takes place analogously to Example 1 using a polysiloxaneconsisting of trimethylsiloxy, dimethylsiloxy and(3-hydroxypropyl)methylsiloxy units with a carbinol group content of0.37% by weight and a viscosity of about 650 mPa·s (at 25° C.). When thereaction is complete, the neutral reaction mixture is acidified with 10%strength HCl, the ethyl acetate phase is separated off, and the mixtureis concentrated by evaporation. This gives theα,ω-(2-carboxyethyl)-modified polydimethylsiloxane as a virtuallycolorless, clear oil with a carboxy group content of 0.98% by weight.

1.-18. (canceled)
 19. A method for preparing organosilicon compounds (2)comprising carboxy radicals and units of the formulaA_(a)R_(b)X_(c)H_(d)SiO_((4-a-b-c-d)/2)  (III), where each A isidentical or different and is a radical of the formula

by oxidizing organosilicon compounds (1) comprising carbinol radicalsand units of the formulaA′_(a)R_(b)X_(c)H_(d)SiO_((4-a-b-c-d)/2)  (I), where Each A′ isidentical or different and is a radical of the formula

where Y¹ is a di- or polyvalent, linear or cyclic, branched orunbranched organic radical optionally substituted and/or interrupted bygroups comprising at least one of the atoms N, O, P, B, Si or S, Y²independently is a hydrogen atom, an organic or inorganic cation, or amonovalent optionally substituted hydrocarbon radical optionallyinterrupted by heteroatoms, y corresponds to the valency of radical Y¹and is ≧2, R each is identical or different and is a monovalent,SiC-bonded optionally substituted hydrocarbon radical, X each isidentical or different and is a chlorine atom, the group A′ or a radicalof the formula OR¹, where R¹ is a hydrogen atom or a monovalentoptionally substituted hydrocarbon radical optionally interrupted byheteroatoms, a is 0, 1 or 2, b is 0, 1, 2 or 3, c is 0, 1, 2 or 3, and dis 0, 1, 2 or 3, with the proviso that the sum a+b+c+d is ≦4 and theorganosilicon compound of the formula (I) has at least one radical A′per molecule and the organosilicon compound of the formula (III) has atleast one radical A per molecule; in the presence of a mediator (3)comprising an aliphatic, cycloaliphatic, heterocyclic or aromatic NO—,NOH— or

containing compounds or mixtures thereof, and an oxidizing agent (4),with the proviso that the reaction is carried out while controlling thepH to a pH≧3.
 20. The method of claim 19, wherein when the reaction iscomplete, the reaction mixture is acidified to a pH of ≦3 using acidswhose pK_(a) value is less than the pK_(a) value of the carboxy group inthe organosilicon compounds (2) comprising carboxy radicals, and theorganosilicon compounds (2) comprising carboxy radicals are obtained inthe form of their free acids.
 21. The method of claim 19, wherein theorganosilicon compounds (1) comprising carbinol radicals have a formulaA′_(v)R_(w)X_((3-v-w))Si  (I′), where v is 0, 1, 2 or 3, w is 0, 1, 2 or3, with the proviso that at least one radical A′ is present.
 22. Themethod of claim 19, wherein the organosilicon compounds (1) comprisingcarbinol radicals have a formulaA′_(v)R_(3-v)SiO(SiR₂O)_(n)(SiRA′O)_(o)SiR_(3-v)A′_(v)  (I″), where v is0, 1, 2 or 3, n is 0 or an integer from 1 to 2000, o is 0 or an integerfrom 1 to 2000, with the proviso that at least one radical A′ is presentper molecule.
 23. The method of claim 22, wherein v is 0 or 1 and o is 0to
 500. 24. The method of claim 19, wherein the organosilicon compounds(1) comprising carbinol radicals have the formula[A′_(v)R_(3-v)SiO_(1/2)]_(s)]SiO_(4/2)]  (I′″), where v is 0, 1, 2 or 3,s can assume a value of from 0.2 to 6, inclusive and describes thenumber of M units [A′_(v)R_(3-v)SiO_(1/2)] per Q unit [SiO_(4/2)], withthe proviso that at least one radical A′ per molecule is present. 25.The method of claim 24, wherein v is 0 or 1 and s is 0.4 to 4 inclusive.26. The method of claim 19, wherein the organosilicon compounds (2)comprising carboxyl radicals obtained are those of the formulaA_(v)R_(w)X_((3-v-w))Si  (III′), where v is 0, 1, 2 or 3, w is 0, 1, 2or 3, with the proviso that at least one radical A is present.
 27. Themethod of claim 26, wherein v is 0 or
 1. 28. The method of claim 19,wherein the organosilicon compounds (2) comprising carboxyl radicalsobtained are those of the formulaA_(v)R_(3-v)SiO(SiR₂O)_(n)(SiRAO)_(n)SiR_(3-v)A_(v)  (III″), where v is0, 1, 2 or 3, n is 0 or an integer from 1 to 2000, o is 0 or an integerfrom 1 to 2000, with the proviso that at least one radical A is present.29. The method of claim 19, wherein the organosilicon compounds (2)comprising carboxyl radicals obtained are those of the formula[A_(v)R_(3-v)Sio_(1/2)]_(s)[SiO_(4/2)]  (III′″) where v is 0, 1, 2 or 3,s can assume a value of from 0.2 to 6 inclusive and describes the numberof M units [A_(v)R_(3-v)SiO_(1/2)] per Q unit [SiO_(4/2)], with theproviso that at least one radical A is present.
 30. The method of claim19, wherein the mediator (3) comprises a nitroxyl radical of theformulae

where R¹⁶ each is identical or different and is a phenyl,aryl-C₁-C₅-alkyl, C₁-C₁₂-alkyl, C₁-C₅-alkoxy,C₁-C₁₀-carbonyl-C₁-C₆-alkyl radical, where the phenyl radicals areunsubstituted or mono- or polysubstituted by a radical R¹⁸, and thearyl-C₁-C₅-alkyl, C₁-C₁₂-alkyl, C₁-C₅-alkoxy, C₁-C₁₀-carbonyl andcarbonyl-C₁-C₆-alkyl radicals may be saturated or unsaturated, branchedor unbranched and may be mono- or polysubstituted by a radical R¹⁸,where R¹⁸ each is identical or different and is a hydroxy, formyl, orcarboxy radical, an ester or salt of a carboxy radical, or a carbamoyl,sulfono, sulfamoyl, nitro, nitroso, amino, phenyl, benzoyl, C₁-C₅-alkyl,C₁-C₅-alkoxy radical, or C₁-C₅-alkylcarbonyl radical, R¹⁷ each isidentical or different and is a hydrogen atom or hydroxy, mercapto,formyl, cyano, carbamoyl, carboxy radical, ester or salt of a carboxyradical, sulfono radical, ester or salt of a sulfono radical, sulfamoyl,nitro, nitroso, amino, phenyl, aryl-C₁-C₅-alkyl, C₁-C₁₂-alkyl,C₁-C₅-alkoxy, C₁-C₁₀-carbonyl and carbonyl-C₁-C₆-alkyl radical, phospho,phosphono, phosphonooxy radical, or ester or salt of a phosphonooxyradical, where the carbamoyl, sulfamoyl, amino, mercapto and phenylradicals are unsubstituted or mono- or polysubstituted by a radical R¹²,and the aryl-C₁-C₅-alkyl, C₁-C₁₂-alkyl, C₁-C₅-alkoxy, C₁-C₁₀-carbonyland carbonyl-C₁-C₆-alkyl radicals are saturated or unsaturated, branchedor unbranched and are optionally mono- or polysubstituted by a radicalR¹², and a [—CR¹⁷R¹⁷—] group are optionally replaced by oxygen, anoptionally C₁-C₅-alkyl-substituted imino radical, a (hydroxy)iminoradical, a carbonyl function or a vinylidene function optionally mono-or disubstituted by R¹², and two adjacent groups [—CR¹⁷R¹⁷—] areoptionally replaced by a group [—CR¹⁷═CR¹⁷—], [—CR¹⁷═N—] or [CR¹⁷═N(O)],where R¹² each is identical or different and is a hydroxy, formyl,cyano, or carboxy radical, an ester or salt of a carboxy radical, acarbamoyl, sulfono, sulfamoyl, nitro, nitroso, amino, phenyl,C₁-C₅-alkyl, C₁-C₅-alkoxy, C₁-C₅-alkylcarbonyl radical.
 31. The methodas claimed in claim 30, characterized in that the nitroxyl radicals ofthe formulae (XI) and (XII) are linked to a polymeric structure via oneor more radicals R¹⁷.
 32. The method of claim 30, wherein at least onemediator (3) is selected from the group consisting of2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO),4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl,4-acetamido-2,2,6,6-tetramethylpiperidin-1-oxyl,4-acetoxy-2,2,6,6-tetramethylpiperidin-1-oxyl,4-benzoyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl and PIPO (polymerimmobilized piperidinyloxyl).
 33. The method of claim 19, wherein themediator (3) is present in an amount of from 0.01 to 100 mol %, based onthe amount of carbinol groups present in the organosilicon compound. 34.The method of claim 19, wherein oxidizing agent (4) is selected from thegroup consisting of air, oxygen, hydrogen peroxide, organic peroxides,perborates, persulfates, organic and inorganic peracids, salts andderivatives of the peracids, chlorine, bromine, iodine, hypohalic acidsand salts thereof, halic acids and salts thereof, halogen acids andsalts thereof, Fe(CN)63- and N-chloro compounds, optionally incombination with enzymes.
 35. The method of claim 34, wherein at leastone oxidizing agent comprises bleaching liquor.
 36. The method of claim19, wherein the oxidizing agent (4), if it is a 2-electron oxidizingagent, is used in amounts of from 0.2 to 250 mol %, and if it is a1-electron oxidizing agent, in amounts of from 0.4 to 500 mol %, in eachcase based on the molar amount of the carbinol groups present in theorganosilicon compounds.
 37. The method of claim 19, wherein theoxidizing agents (4) are metal oxides or anodes of an electrolysis cell.38. The method of claim 19, wherein the method is carried outcontinuously.